Diaminodiphenylsulfone glycidyl resins



3,014,895 DIAMINODIPIENYLSULFONE GLYCIDYL RESINS Harold C. Reynolds, Plainfieid, Ni, Robert C. ONeili,

New York, N.Y., and John D. Garber, Westfield, N.5., assignors to Merck & Co., Inc., Railway, N31, a corporation of New Jersey No Drawing. Filed Mar. 19, 1958, Ser. No. 722,380 11 Claims. (Cl. 260-793) This invention relates to glycidyl diaminodiphenylsulfonesv The compounds of the present invention include mono mers having the general formula:

where R nd R are selected from the group consisting of hydrogen and the glycidyl radical having the formula and to polymers of the above compounds. Monomers contain either one, two, or three glycidyl radicals per molecule as shown in the above formula.

The products of this invention are a new class of compounds which may be termed expoxy-polyamine reaction products. The compounds of the present invention are surprisingly stable in view of the fact that they contain both amino and epoxy groups which normally interact even at room temperature. While applicants do not Wish to be bound by any theory, the absence of such interaction at ordinary temperatures in the compounds of this invention is apparently due to the low basicity of diaminodiphenylsulfone.

High heat distortion points, in some cases as high as 300 C., and good chemical resistance, are characteristic of polymers of this invention. Because of this combination of properties, these polymers are useful in various applications Where metal or ceramic formerly was required. A further advantage of the resins of this invention is that no curing agent is necessary. This eliminates numerous difliculties associated with curing agents, such as inaccurate proportioning and inadequate mixing, premature curing, handling problems due to toxicity or irritation (particularly in the case of aliphatic amines), low solubility of curing agents, and deleterious effects of residual functional groups on electrical properties and chemical resistance.

The compounds of the present invention are made by reacting epichlorohydrin with 4,4'-diaminodiphenylsultone, and converting the resulting reaction product with an alkali metal hydroxide or other base to a glycidyl diaminodiphenylsulfone. The glycidyl diaminodiphenylsulfones polymerize at elevated temperatures to form a variety of resins.

The reactions which can be carried out according to this invention may be illustrated by the following equation:

3,0l4,85 Patented Dec. 28, 1961 In the above equation R and R are either hydrogen or the glycidyl radical as previously indicated, Y and Y are either hydrogen or the 3-chloro-2-hydroxypropyl radical having the formula.

and x is an integer having a value of 1 to 3 inclusive. The foregoing equation indicates the quantities of reagents actually entering into reaction.

Reaction of diaminodiphenylsulfone (I) with epichlorohydrin (H) is the first step in the process according to the present invention. The mole ratio of epichlorohydrin to diaminodiphenylsulfonc in the reactant feed is r governed by the type of end product desired. Generally approximately stoichiometric quantities of reagents are used. For example, Where the desired final product is diglycidyl diaminodiphenylsulfone or a polymer thereof, the mole ratio of epichlorohydrin to diaminodiphenylsulfone is about 2:1. The product of this reaction step is predominantly di(3-chl0ro-2-hydroxypropyl)diaminodiphenylsulfone, with some monoand tri(3-chloro-2-hydroxypropyl)-diaminodiphenylsulfone also formed. Reaction products consisting predominantly of either mono- (3 chloro 2 hydroxypropyl)diaminodiphenylsulfone or tri 3 -chloro-2-hydroxypropyl diaminodiphenylsulfone can be formed from a reactant mixture of epichlorohydrin and diaminodiphenylsulfone in the approximate mole ratios, 1:1 and 3:1 respectively. An excess of either reagent can be used, however; and the mole ratio of epichiorohydrin to diaminodiphenylsulfone may be in the range of about 0.821 to about 5:1.

The reaction of epichlorohydrin with diaminodiphenylsulfone may be carried out in a solvent medium such as dioxane, tetrahydrofuran, acetone, excess epichlorohydrin, or in the absence of a solvent. It is preferred to add a Lewis acid catalyst such as boron trifluoride, a complex boron trifluoride with another substance such as the 1:1 (mole ratio) boron trifluoride-diethyl ether complex, zinc chloride, and the like. This reaction is carried out at elevated temperatures. The presence of unreacted epichlorohydrin is readily determinable by heating a small sample of the reaction product with a solution of lepidine in diethylene glycol. A bright blue color develops if epoxide groups are present.

The reaction products (111) are solid materials which can be isolated from solution by evaporation of the solvent, and subsequently redissolved and dehydrohalogenated. It is not necessary to recover these reaction prodnets in solid form. Instead, they can be dehydrohalogenated directly without removal of solvent.

The reaction product (III) of diaminodiphenylsulfone and epichlorohydrin is dehydrohalogenated with a base such as sodium hydroxide, potassium hydroxide, calcium oxide, calcium hydroxide, alkali silicate, or sodium carbonate in a suitable solvent such as tetrahydrofuran, acetone, or dioxane, or in the absence of a solvent. This reaction may be carried out at elevated temperatures such as reflux temperature. The product (IV), which is a mixture of mono-, di-, and triglycidyl diaminodiphenylsulfone, plus dimers thereof, can be recovered as a solid or liquid product by evaporation of the solvent. Evaporation at reduced pressure is useful in order to prevent or minimize polymer formation. The glycidyl diaminodiphenylsulfones can be stored at room temperatures for long periods of time without polymerization. As a further safeguard against polymer formation, the monomer can be stored as a solution in a solvent such as tetrahydrofuran, dioxane, or the like.

Polymers of this invention are formed simply by heating the monomer to curing temperature. Curing is carried out as a rule at temperatures of about to 3 C., and can be followed by a post-curing period at higher temperatures of about 170 to 200 C.

A wide variety of polymers can be formed according to the present invention. The properties of the polymer are influenced to a considerable extent by the number of glycidyl units per mole of glycidyl diphenylsulfone monomer.

Monoglycidyl diaminodiphenylsulfone polymerizes with itself to form linear or branched thermoplastic polymers. These polymers may be used as bonding layers in laminates. They may also be copolymerized with various polymer-forming materials such as ethylene oxide, propylene oxide, phthalic anhydride, diamines, the diglycidyl ether of bis-phenol A, and fatty or resin acids, to form thermosetting resins.

Diglycidyl diaminodiphenylsulfone polymerizes with itself to form thermosetting epoxy resins which are useful for potting or encapsulating electrical components, and in making laminates with glass fiber or cloth. Shrinkage on curing is very slight. These resins are hard at room temperatures and at the elevated temperatures encountered in electrical apparatus such as motors. The heat distortion points range from about 150 to 300 C., or even higher.

Polymers of triglycidyl diaminodiphenylsulfone are prepared in the same manner as the polymers of diglycidyl diaminodiphenylsulfone and have similar properties.

An outstanding feature of this invention in one aspect is the elimination of curing agents. However, it is possible to polymerize the monomers of thi invention using curing agents when properties other than those of the unmodified polymers are desired. Various curing agents, particularly amines such as diaminodiphenylsulfone, diethylene triamine, m-phenylene diamine, terpene diamine, or anhydrides such as phthalic, pyromellitic anhydride, and the like may be used. Acidic materials such as boron trifluoride and various complexes thereof, e.g. the condensation product of boron trifluoride and ethylamine, are also suitable as curing agents.

Copolymers of glycidyl diaminodiphenylsulfoue with other materials can be made according to this invention. Among the materials suitable for copolymerization are epoxy resins, phenolic resins, polyamides, proteins, polyethylene imines and the like.

The examples which follow illustrate specific embodiments of the present invention.

The Barcol hardness measurements in the following examples are the readings obtained with a Barcol Model GYZJ9341 Impressor, made by the Barber-Colman Co., by Rockford, Illinois. Heat distortion points were determined by measuring hardness at various temperatures and extrapolating to zero Barcol hardness.

Spot check analyses for the presence of epoxy groups were made by taking a 0.1-ml. sample of the solution to be analyzed, adding an equal volume of a 5% solution of lepidine in diethylene glycol, and heating the mixture in a test tube to the boiling point of diethylene glycol. A dark blue color indicates the presence of epoxy groups. Quantitative determinations of epoxy groups were made according to the procedure reported by E. C. Dearborn et al., Ind. Eng. Chem., 45, 2715 (1953), and the results are reported herein as the epoxide equivalent weight.

EXAMPLE 1 (A) Monoglycidyl diaminodiphenylsulfone monomer A solution of 49.6 g. (0.2 mole) of diaminodiphenylsulfone in 100 ml. of dioxane was heated to boiling and cooled slightly. To this solution 0.5 ml. of a 47% solution of 1:1 (mole ratio) boron trifluoride-ether complex in ether was added. This was followed by dropwise addition of 18.5 g. (0.2 mole) of epichlorohydrin over a half-hour period. The warm solution was stirred and slowly cooled. Stirring was continued for a total of two diphenylsulfone, having the formula ENG-so2-Nnonrpn-omc1 Yield 68.6 g.

Analysis.Calculated: N, Found: N, 8.56%; Cl, 9.24%.

The (3-chloro 2 hydroxypropyl)diaminodiphenylsulfone was dissolved in 200 ml. of warm tetrahydrofuran. The solution was cooled to room temperature and 14.0 g. (0.264 mole) of powdered potassium hydroxide was added in portions. After the addition of potassium hydroxide was complete, the solution was heated to reflux and maintained at that temperature for 45 minutes with stirring. The stirring was then stopped and the slurry ermitted to settle. The supernatant liquid was tested for chlorine, which test was negative. The slurry was filtered. The filtrate consisted of 230.3 g. of a solution of the product in tetrahydrofuran. The amount of product glycidyl diaminodiphenylsulfone in the solution was 60.8 g. This product was essentially the monoglycidyl diaminodiphenylsulfone having the formula The solid monoglycidyl diaminodiphenylsulfone was recovered by distillation of the tetrahydrofuran at 3 mm. pressure and room temperature. The last traces of tetrahydrofuran were removed by dissolving the product in acetone and adding other until precipitation occurred. The mixture of acetone, ether, and traces of tetrahydrofuran was decanted and discarded. This procedure was repeated three times. The product was then dissolved in acetone, precipitated with benzene, the liquid mixture of acetone and benzene decanted. The product was frozen in a Dry Ice-acetone mixture and dried to a powder at 2 mm. pressure in the frozen state. Yield 45.7%; M.P. 70 C.; epoxide equivalent weight 387 (theoretical 304).

Analysis.Calculated: C, 59.25%; H, 5.30%; N, 9.22%. Found: C, 59.38%; H, 5.02%; N, 8.59%.

(B) Polymerization of monoglycidyl diaminodiphenylsulfone The monoglycidyl diaminodiphenylsulfone powder prepared as above-described was heated at 100 C. for onehalf hour, and then placed in a mold and heated at 180 C. and 10,000 pounds per square inch pressure for one and one-half hours. A hard dense mass of cured polymer having a Barcol hardness of 30 at 25 C. resulted.

EXAMPLE 2 (A) Diglycidyl diaminodiphenylsulfone monomer To a solution of 496 g. (2 moles) of diaminodiphenylsulfone in 1 liter of acetone, 10 ml. of a 47% (by weight) solution of boron trifluoride-ether complex in ether was added. The solution was heated to reflux while stirring. To the hot solution 370 g. (4 moles) of epichlorohydrin was added dropwise with a slight evolution of heat. Refluxing with stirring was continued for 18 hours. At that time a negative lepidine test indicated the absence of epoxide. Heating was discontinued. The solvent was removed by distillation at 5 mm. pressure and C. A red solid product, which was essentially di(3- 6 chloro-2-hydroxypropyl)diaminodiphenylsulfone monodioxane, and 19.8 g. (0.31 mole) of powdered potassium mer having the formula hydroxide was added. The solution was refluxed for 01CH2OHCH2NH-SO2-NHOHCHCH2C1 H AR was obtained. Yield 870.5 g. (100%). five hours, during which time a precipitate was formed. Analysis-Calculated: N, 6.47%; Cl, 16.40%. Found: This precipitate was filtered oil? and analyzed for chlorine N, 6.80%; Cl, 13.51%. content. Analysis indicated 96% removal of the chlo- The mole ratio of chlorine to nitrogen (0.81421), rine originally present in the solution. The filter cake coupled with infra-red absorption data, indicates that was discarded. The filtrate was evaporated at 2 mm. over 80% of the nitrogen atoms were mono-substituted. pressure and 25 ;C. to remove the solvent dioxane. The The di(3-chloro-2-hydroxypropyl)diaminodiphenylsulfinal product diglycidyl diaminodiphenylsulfone monomer fone was dissolved in 850 ml. of tetrahydrofuran. The thus obtained was an oil containing 82.7% solids and the solution was heated to a temperature slightly below rebalance residual dioxane. The epoxide equivalent weight flux temperature with stirring, and 227 g. (4 moles) of was 334 (theoretical value 180).

powdered potassium hydroxide was added. Stirring was Analysis.-Calculated: C, 59.9%; H, 5.59%; N, 7.77%.

continued for four hours at reflux temperature. The Found: C, 59.36%;H, 6.00%;N, 6.78%.

potassium hydroxide gradually dissolved and crystalline potassium chloride gradually precipitated. After four (B) Polymenzanon of dlglycldyl dmmmodlphenylsul'fone v Monomer hours the stirring was stopped, and the slurry was permitted to settle. A test of the supernatant solution in- The product monomer obtained above was heated dicated no chlorine. The slurry was filtered, and suffor 16 hours at 130 C. and then for three hours at 170- ficient solvent was evaporated at 90 to 100 C. and 20 190 C. The cured resin had a Barcol hardness of 32 mm. pressure to yield 941 g. of a 80% solution of at C. and an apparent heat distortion point of 156 C.

diglycidyl diaminodiphenylsulfone in tetrahydrofuran 25 (equivalent to 754 g. of solid diglycidyl diaminodiphenyl- EXAMPLE 4 sulfone). The epoxide equivalent weight, determined on an aliquot of the solution, was 248 (theoretical value 180). The solvent was removed by heating at 4 mm. A mixture of 49.6 g. (0.2 mole) of diaminodiphenylpressure and maximum temperature of 170 C. The sulfone and 1 ml. of 47% borontrifiuoride-ether comproduct diglycidyl diaminodiphenylsulfone, which had plex in 100 ml. of acetone was heated to reflux. To the (A) Triglycidyl diaminodiphenylsulfone monomer the formula hot solution 74.0 g. (0.8 mole) of epichlorohydrin was oH2-on oHQNHGSOQGNHCHFCEFCE was in the molten state upon completion of the removal added dropwise. Refluxing was continued for 24 hours, of solvent. A portion of the product was allowed to at the end of which time a negative lepidine test indicated solidify and analyzed. the absence of epoxy groups. The solvent was evaporated Analysis.-Calculated: C, 59.6%; H, 5.59% N, at 29 inches of mercury vacuum and a temperature of 7.77%. Found: C, 60.57%; H, 5.62%; N, 7.17%. 90 to 100 C. A syrupy product, which was essentially tri(3 chloro 2 hydroxypropyl)diaminodiphenylsulfone having the formula (ClOHr-SJH-OHzhNGSOzQNHCHz-{JH-C H201 on da (B) Polymerization of diglycidyl diaminodiphenylsulfone remained.

monomer Analysis-Calculated: N, 4.53%; 01, 20.5%. Found: The molten diglycidyl diaminodiphenylsulfone mono- 50 N, 4.52%; Cl, 17.80%.

mer, prepared as described above, was cast into an alu- The tri(3-chloro-2-hydroxypropyl)diaminodiphenylsulminum mold and heated in an oven at 100 C. for five tone was dissolved in 100 ml. of tetrahydrofuran at room hours and then at 180 C. for one and one-half hours. temperature, 45 g. 0.8 mole) of powdered potassium A hard cake of cooled resin which shrank little on coolhydroxide was added. The amount of heat evolved was ing was formed. The Barcol hardness at 25 C. was not suflicient to raise the temperature to reflux. The 52 and the apparent heat sto o P mixture was stirred and allowed to cool over a two-hour EXAMPLE 3 period to 25 C. At that time the stirrer was stopped and the slurry permitted to settle. A test on the super natant solution for chlorine was negative. The slurry A solution f 24.8 (0.1 mole) of diaminodiphenyl- 0 was filtered. The solvent was distilled from the filtrate sulfone, 18.5 (0.2 mole) of epichlorohydrin, 4 ml. of at a low pressure of 2 The product remaining was 4 7% olution of boron trifluoride-ether complex i essentially triglycidyl diaminodiphenylsulfone having the ether, and 50 m1. of dioxane was gently refluxed for 20 formula (A) Diglycia'yl diaminodiphenylsulfone monomer hours. The flask containing the residue of di(3-chloroand an epoxide equivalent weight of 161 (theoretical value 2-hydroxypropyl)-diaminodiphenylsulfone was placed in Yield 8-; molecular Weight 612 delfifmined an oil bath which was maintained at 200 C. and the by depression of the freezing point of dioxane); E%,

dioxane evaporated at 2 mm. pressure. The dried prod- 781 at 308 m 441 at 271 mp methanol). not was a black oil having an odor of dioxane. Yield 36.5 g. (B) Polymerization of triglycidyl diaminodiphenylsulfone Analysis.Calculated: N, 6.47%; Cl, 16.40%. Found: N, 5.86%; Cl, 14.71%. The product obtained in Example 6 was cured for 19 The black oil product was redissolved'in 150 ml. of 75 hours at C., followed by three hours at C.

8 The polymer thus obtained had a Barcol hardness of 41 at where R and R are selected from the group consisting 26 C. and an apparent heat distortion point of 176 C. of hydrogen and the radical EXAMPLE 5 --CH2-C&;CH2 Diaminodiphenylsulfone-cured resin 5 To 30 g. of diglycidyl diaminodiphenylsulfone was Th compound havmg the formula added 1.7 g. of diaminodiphenylsulfone. The mixture was cured for three hours at 175 C., producing a hard HgN SO NHCm g cured resin, having a Bareol hardness of 23 at 25 C. O and a heat distortion point of about 142 C. 3. The compound having the formula 4 The compound having the formula EXAMPLE 6 5. Compounds having the general formula Acid-cured diglycidyl diaminosulfone resin N SO NHCH OHCH G1 An acid-cured diglycidyl dlammodiphenylsulfone resin 25 G 7 2 was prepared by mixing 30 g. of diglycidyl diaminodiphenylsulfone with 0.35 g. of a condensation product of where Y and Y are selected from the group consisting boron trifluoride and ethylamine, and curing for hours f hy g n an he radical having the f rmula at 100 C., followed by three hours at 175 C. The GHT CH OH2C1 resulting resin had a Barcol hardness of 39 at C.

and an apparent heat distortion point of about 158 C. $3

6. The compound having the formula EXAMPLE 7 Copolymer of diglycidyl diaminodiphenylsulfone with di- 2 -SONHOHzC 2Cl glycidyl bis-phenol A )11 A copolymer of bis(4-glycidoxyphenol)dimethylmeth- 7. The compound having the formula 8. The compound having the formula ane and diglycidyl diaminodiphenylsulfone was prepared 9. The insoluble, infusible polymer obtained by heatby mixing 217 g. of the former with 30 g. of the latter ing a compound of the formula and curing for three hours at 175 C. The product R1 was a hard resin having a Barcol hardness of 33 at 25 C. and a heat distortion point of about 171 C. E7

EXAMPLE 8 O at a temperature of about 90140 C. for from about Glass cloth laminate one-half to nineteen hours in the absence of a solvent,

Seven squares of woven glass cloth which had been Where 1 and 2 are selected from the group Consisting treated with steratochromyl chloride (Volan A, made of y o and the Iadlcal by E. I. du Pont de Nemours, Inc., Wilmington, Delaware) CH CHCHz to increase adherence of solutions of monomer, were 0 dipped in a 50% solution of diglycidyl diaminodiphenylsulfone monomer (prepared as described in Example 2) P 9 for making y yin tetrahydrofuran. The cloth squares were air-dried to P PYD dlammodlPhenylsulfone of the formula a tacky state and joined to form a laminate. The laminate Y1 was initially cured at 100 C. for one hour between heated Q NHOH2CH .CH2G1 platens at contact pressure of less than 50 p.s.i. Final g curing was effected at 180 C. for 90 minutes to yield a H tough, stiif, insoluble sheet. wherein Y and Y are selected from the class consisting While the present invention has been described with of hydrogen and the 3-chloro-2-hydroxypropyl radical, reference to specific embodiments thereof, it is evident that comprises reacting together diaminodiphenylsulfone that various modifications can be made without departand epichlorohydrin at elevated temperature in the presi g from the present invention. ence of a catalyst selected from the group consisting of What is claimed is: boron trifiuoride and boron trifluoride-ether complex. 1. Compounds having the general formula 11. The process for making a compound of the formula R1 R1 N SO NHCH CHCH N- -SO NHCH CHCH 9 10 wherein R and R are selected from the group consisting and heating said latter substance in the presence of an of hydrogen and the radical alkali metal hydroxide.

CH? gy References Cited in the file of this patent 5 UNITED STATES PATENTS that comprises reacting dlamlnodlphenylsulfone w1th epichlorohydrin at elevated temperature in the presence 1,977,251 Stanmann 16, 1934 of a catalyst selected from the class consisting of boron 1,977,253 Stanmann 1934 trifiuoride and boron trifiuoride-ether complex to form 2,131,120 Schlack 9 1938 a compound of the formula 10 9 3 Beavers 1956 2,884,406 Wegler et al. Apr. 28, 1959 2,897,179 Schecter et a1. July 28, 1959 Q Q ZZ OTHER REFERENCES 15 Chemical and Engineering News, page 98, Mar. 18,

where Y and Y are selected from the class consisting 1957. of hydrogen and the radical Chemical Abstracts, vol. 49, No. 2, January 1955, p.

1101. CH2 CH OHZCI Moeller: Inorganic Chemistry, Wiley & Sons (1952),

H 20 pp. 326-328.

UNITED STATES PATENT, OFFICE CERTIFICATE OF CORRECTION Patent No. 3,014.895 December 26 1961 Harold C Reynolds et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

for the left-hand portion of the Column 8, claim 1 "CH NH F6815? 2N """e formula reading "GH -CH o 0 Signed and sealed this 24th day of April 1962,

(SEAL) Attest:

ESTON c. JOHNSON DAVID DD Attesting Officer Commissioner of Patents 

11. THE PROCESS FOR MAKING A COMPOUND OF THE FORMULA 